Three Ireland appear to be throttling repeated tests

[Sean]

I recently found out I can get 4G at my workplace.  I had to use my old HTC One SV as it turns out Three Ireland is using band 20 (800MHz) from what I can tell, which it acquired through buying out O2 as they didn't have licensed spectrum in this band beforehand.  My OnePlus One does not support band 20, so shows no coverage when forced to 'LTE Only' here, but works fine on 4G in band 3 areas such as Dublin.

 

With my old HTC phone, I headed to TestMy and started running speed tests all over the place as one would.

 

However, one thing I quickly noticed was that each successive speed test was slower than the previous one and figured it must be network congestion that day.

 

This morning at my workplace, I ran a speed test and got this result:

 

 

I started walking about the place running the odd upload & download test here & there and again the speeds fell way down.  Although the upload speed was fairly consistent, the part where it had to download a block got incredibly long (2 minutes I think) for 6MB of data, only to upload it in a few seconds!

 

Then I tried an idea - place a 5MB image on my blog and run the TestMy Mercury test with its link.  The following are the two results run one after the other - Mercury on left and UK linear on the right:

 

 

When I took the SIM card out of my phone and put it in the OnePlus to rerun the UK download test, it was fine again.  So I put the SIM back into the HTC and when I ran the UK server test, it was back to about normal again:

 

 

Pity the Google CDN is going as that's giving me the quickest results, as I'm sure Three are not going to throttle Google:

 

 

So for anyone else noticing unusually slow results (at least on the Three network), it might be worth powering off & on the phone or ejecting the SIM card (if possible, as I did.)

[Sean]

I did some further testing this time using my OnePlus phone which can only connect to 3G here.

 

What I did was ran a handful of speed tests until my throughput fell way down, then connected to the HMA VPN service (UK server) and repeated the test.  Unsurprisingly the speed shot way up.  I repeated with the VPN disconnected and it was back to a snail's pace:

 

Test using UK server - no VPN and with VPN:

 

The speed while connected to the VPN fluctuated about and seemed to slow down to just above 5Mbps with the London VPN server.  Test results were similar between single and multithreaded tests.  The following are two further examples, with the right being the highest I recorded, pretty impressive for a 3G connection, not mention over a VPN on top of that!

 

 

But once I disconnect the VPN and repeat the speed test, it's back down to a snail's pace:

 

 

I must bring my old HTC phone to work again to try VPN tests with it over 4G.

[Sean]

I've carried out some VPN tests over the past number of days and it appears that they block VPN connections in certain areas on their 4G network.

 

With the 4G signal I pick up at my workplace, VPN connections work fine and the speed is fairly consistent using a VPN server in London.  The left is the upload & multithreaded download test and the right is a linear transfer:

 

 

However, with the 4G signal I pick up in Letterkenny, I cannot use VPN at all.  I tried various VPN servers, including my workplace VPN.  The VPN connection itself will establish, but any transfer over it will fail.  When I switch the phone to 3G mode, VPN connections work fine, but not when I switch back to 4G.  I tried my brother's Nokia Windows 4G phone with the same result. 

 

The 4G connection itself was fine as I had no problem playing YouTube in HD and was getting download speeds of 15Mbps to about 30Mbps with the Google CDN depending on the signal strength, even Friday evening when my home ISP NWE normally slows way down. 

[CA3LE]

Does your web browsing slow down significantly when you're seeing the issue?

[Sean]

Yes - many websites are noticeably slower to load, particularly the images.  Even just trying to bring up the TestMy homepage before I can run the test can be a tedious wait.  But with the VPN connected, the pages load up straight away. 

 

Major websites such as BBC News and HTTPS websites seem to load pretty quick without the VPN, so they seem to be mainly throttling HTTP port 80.

[Sean]

It looks like they are tinkering with the throughput as this morning the speed did not slow down after performing a handful of 50MB size tests.  Maybe one of their technicians saw this thread...  Usually the throughput sharply falls after a 25MB test or two.  I suspect the upload is throttled as I have seen much faster uploads in the past and usually the uplink is less congested than the downlink, especially around 9am!  The following is a multithreaded test with the UK server and a linear test after downloading 300 MB by this stage:

 

 

I also got the fasted 4G test on my phone this morning, in this case using the Google CDN.  I pulled in at the town Bruckless on my way to work where someone told me they picked up 4G.  The signal was just 2 bars:

 

 

Then again, Three Ireland do plan charging €5/month extra in July to use their 4G network, so it could be they are doing some tweaks to ensure 4G clearly stands out to entice its users to pay the premium. 

 

It's also hard to believe just how much data all this testing gobbles.  Going by the phone's data usage, I used 3.42GB since the 29th May.

[Sean]

It seems like Three is back to throttling traffic to some extent again on individual connections.  Over the past couple of days, I have been getting pretty poor linear test results on their network, so decided to check at my workplace where I get a strong signal on both 3G and 4G.

When I ran the test with my phone forced to use 3G, the following is the result:

When I repeated the test with the phone on LTE (4G), I actually got a slower test result:

The only way I could get a faster test result on 4G was by performing a multi-threaded test, similar to what Ookla's app descretely does all the time:

As I bought a 3UK SIM for my recent trip to the US, I tried that SIM which roams on 3 Ireland and still has some data credit left.  While it will not roam on the 4G network here, its 3G test result is a vast improvement on the above single threaded tests:

I continued to run various tests with both SIM cards and continued to get similar results.  With linear tests, my main SIM averaged about 6.2mbps with jaggy or slopped downward graphs using a mix of 3G and LTE tests.  The Three UK SIM averaged about 10.4Mbps on 3G only with fairly flat graphs.  The phone placed in the same spot for both tests and the 3UK SIM roamed on 3 Ireland, so in theory was using the same cellular tower as my main Irish 3 SIM.

[Sean]

With TestMy implementing a https speed test, I am now fairly confident Three Ireland is back to throttling http traffic again.

The following are three speed tests - UK Server linear, German Server linear and UK Server multithreaded.  The phone was kept in the same spot for each test, had a full LTE (4G) signal and I chose a 25MB block in each test for consistency.

 

When I switched to https (SSL) mode, the difference is quite dramatic with the same 25MB block size:

Multithreaded https tests are not working for me at the moment, but I'm sure I would have got a dramatic speed increase on a multithreaded https transfer also.

Edited October 23, 2015 by Sean

[CA3LE]

With TestMy implementing a https speed test, I am now fairly confident Three Ireland is back to throttling http traffic again.

The following are three speed tests - UK Server linear, German Server linear and UK Server multithreaded.  The phone was kept in the same spot for each test, had a full LTE (4G) signal and I chose a 25MB block in each test for consistency.

When I switched to https (SSL) mode, the difference is quite dramatic with the same 25MB block size:

Multithreaded https tests are not working for me at the moment, but I'm sure I would have got a dramatic speed increase on a multithreaded https transfer also.

That's a dramatic increase!  Wow, I had no idea this was happening out there.